The move follows the signing of an agreement between NITB and the National Trust.

Alan Clarke, Chief Executive of NITB, said: “The Giant's Causeway is the jewel in the crown of NITB's Causeway Coast & Glens Signature Project. NITB funding of £9.25m, and 50% of total project cost of £18.5m, will allow the building of the new visitor facilities to commence very shortly.

“NITB funding has been given on the basis of developing Northern Ireland's only World Heritage Site and number one tourist attraction to provide a world-class tourism offering which will interpret the Causeway and the wider region.

“This will provide opportunities to grow the tourism sector by signposting visitors to other attractions in the region, increasing the time that visitors stay in the region and increasing the amount spent by visitors.

“NITB have been working closely with the National Trust to develop the new facilities and visitor experience to ensure it fits with NITB's ‘visitor inspired' ethos in terms of uncovering the stories associated with the World Heritage Site and the wider regions.”

The National Trust's Northern Ireland Director, Hilary McGrady, said: “This announcement means that now we should be on site by the end of spring. It is just two short years since the National Trust took the lead in this project and we are now literally weeks away from breaking ground.

“I am delighted that the Northern Ireland Tourist Board and the Department of Enterprise, Trade and Investment and have continued to support this massive project and reflect their confidence in our ability to deliver.

“Coupled with the £3m from Heritage Lottery Funds announced in February and the £4m investment by the National Trust, we can now focus even more on our fundraising campaign ‘A Giant Cause' to ensure we raise the remaining £2m required by the time the project is completed.

“With over £215,000 raised, we know this appeal will be a success and I would again encourage our members and the people who help us care for these beautiful places to support this appeal today.”

Work begins in May to create new car parks, to relocate retail and tourist information to the Causeway Hotel and to provide additional toilets and onsite catering kiosks, with park and ride facilities in nearby Bushmills.

In autumn the main build will commence, to build visitor facilities befitting the status of the site, and improved trails and parks. The new building will be completed by summer 2012.

Investment is the final piece in a complex jigsaw

Analysis by David Gordon

As the final piece of grant-aid is added to the jigsaw, the long-awaited start to the building of a new Causeway centre can finally get under way.

The £9m from the Tourist Board comes on top of £3m from the Heritage Lottery Fund.

The visitor centre project was the subject of a somewhat sterile public versus private sector debate in 2007.

An intense controversy also erupted over lobbying by Ian Paisley Jnr for Seymour Sweeney, the developer with rival plans to the National Trust scheme that is about to proceed.

The row cost Mr Paisley his ministerial job by early 2008.

By that stage, Environment Minister and party collegue Arlene Foster had reversed well away from her initial position of being “minded” to grant the Sweeney scheme approval.

There is nothing to suggest that Mrs Foster had been aware of — or influenced by — lobbying in support of the developer.

DUP colleagues had rushed to support her initial “minded” stance. However, within a year or so, the rhetoric had changed. The economy was tumbling into recession and public sector building projects were being hailed as helping to safeguard private sector jobs.

The only mention of Mr Sweeney yesterday came from Jim Allister, the TUV leader taking on Mr Paisley Jnr for the north Antrim seat in the General Election.

He had helped reveal some of the past Paisley lobbying through use of the Freedom of Information Act.

Whether the past Causeway centre controversies will matter on the doorsteps of north Antrim remains to be seen.